The present invention relates to novel metallocenyl-phthalocyanines, to a process for their preparation and to their use.
The field of this invention is that of the optical recording of information for writable recording media, the information being recorded via different optical properties of a dye on written and unwritten places. Corresponding recording media are known, for example, under the name xe2x80x9cWORMxe2x80x9d systems (write once read many) and are further categorised into e.g. xe2x80x9cCD-Rxe2x80x9d or xe2x80x9cDVD-Rxe2x80x9d.
The use of dyes which absorb radiation in the near infrared range (NIR range) for recording information in WORM systems is described, inter alia, by M. Emmelius in Angewandte Chemie, No. 11, pages 1475-1502 (1989). By irradiating such recording materials with laser it is possible to achieve the change in absorption required for recording information in binary form via physical changes (for example by sublimation or diffusion) or via chemical changes (for example photochromism, isomerisations or thermal decomposition of the dye).
Substituted phthalocyanines are an important class of dyes for use in such WORM systems because they have high NIR absorptions in the range from 700 nm to 900 nm when correspondingly substituted and dependent on the central atom which is usually present.
The most stringent requirements are placed on the recording layer to be used, such as high refractive index, high initial reflectivity, narrow absorption bands in the solid state, uniformity of the writing width at different pulse duration, high light stability in daylight as well as under weak laser radiation (readout) coupled with high sensitivity to intense laser radiation (inscribing), low noise, high resolution as well as, most importantly, very little statistical jitter of the pits over a desired value at optimum writing performance.
As the recording layer is normally applied from a solution, typically by spin-coating, the dyes should also be readily soluble in conventional solvents, which are described, inter alia, in EP-A 511 598 (independently from the distinction made therein between polar and nonpolar solvent).
Phthalocyanine compounds containing at least one ferrocene unit as substituent are known. J. Organomet. Chem. 468(1-2) (1994), for example, describes 205-212 1, 1xe2x80x3,1xe2x80x3xe2x80x3,1 xe2x80x3xe2x80x3xe2x80x3(29H,31H-phthalocyanine-2,9,16,23-tetrayl)tetrakis-ferrocene; Quin. Chem. Lett. 4(4) (1993) 339-342 describes [1-(11-ferrocenylundecyl)-1xe2x80x2-[4-[4-[[9,16,23-tris(2,2-dimethylpropoxy)-29H,31H-phthalocyanine-2-yl]oxy]phenoxy]butyl]4,4 xe2x80x2-bipyridiniumato(2-)-N29,N30,N31,N32]-zinc dibromide; New J. Chem. 21(2) (1997) 267-271 describes 1,1xe2x80x3-[[9,23-bis(dodecylthio)29H,31,H-phthalocyanine-2,16-diyl]bis(nitrilomethylidine)]bisferrocene; and J. Organomet. Chem. 541(1-2) (1997) 441-443 describes the synthesis of [Cp(dppe)Fexe2x80x94CNxe2x80x94MnPc]2O (with dppe=1,2-ethanediylbis(diphenylphosphine); Cp=cyclopentadienyl; Pc=phthalocyanine).
J.Chem.Soc., Chem.Commun. 1995,1715-1716 describes the preparation of liquid crystalline ferrocenyl-phthalocyanines, ferrocenecarbonyl chloride being reacted with a hydroxy group-substituted and metal-free phthalocyanine to the corresponding ester compound.
Inorg. Chem. 37 (1998) 411-417 describes the synthesis of bis(ferrocenecarboxylato)(phthalocyaninato)silicium, the ferrocene unit being bound to the central atom.
WO-A 9723354 describes optical recording materials based on phthalocyanines which contain as substituents inter alia ferrocene units bound to the central atom.
The use of CD-R as archiving and back-up media for computer data increasingly requires faster writing speeds. In contrast, use as audio medium requires slower (1x) speeds. Accordingly, the recording layers continuously need to be optimised for such a wide-band behaviour (at present 1x-8x), which places extraordinarily high requirements on the recording layers to be used. It is known that recording layers containing phthalocyanines show very good measurement values for high speeds (2x-6x) but less favourable 1x-values for the length deviation of the pits and lands from the norm, and also for the jitter. Jitter is in effect understood to be a time error at the change of a signal as a result of a pit or a marked range being too short or too long. On a CD-R, for example, the length of the pits can vary between 3T and 11T (1T=231.4 ns). If, for example, the length of a 3T pit is even marginally fallen short of or exceeded, then this may result in an increased number of BLERs (=block error rate, designating the number of physical errors on the CD) and thus in a loss in quality. The error rate (BLER) should as a rule be less than 220 per second.
Different proposals have been made to solve the cited difficulties when using phthalocyanines; in particular attempts were made to lower the decomposition temperature which is higher than that of other dye classes, especially cyanines.
DE-A 4 112 402, for example, proposes to use as recording film a mixture consisting of a phthalocyanine and a cyanine (as light absorber element) which absorbs in the cited wave-length range. However, also in this instance does repeated readout result in the destruction of the light absorber so that the desired properties are not obtained. It is moreover known that cyanine dyes are not lightfast and that it is therefore usually necessary to add a stabiliser.
EP-A 600 427 describes an optical recording medium, the recording layer of which comprises a phthalocyanine and an additive, e.g. a ferrocene derivative, a metal acetylacetonate or an antiknock additive. According to that application, the addition of the cited additives improves the quality of the recording. Disadvantages are, however, the use of an additional substance in the form of an additive and the difficulties in the recovery of the dye which is obtained in the production of the recording layer because, to use the dye again, the additive must either be removed or its amount must be readjusted.
JP-A 8-118800 describes optical recording media, the recording layer of which comprises an azo compound which is substituted by a ferrocene unit. Furthermore, mixtures of these azo compounds with, inter alia, phthalocyanines and pentamethinecyanines are described. The disadvantage in this case is that neither the azo compound nor the phthalocyanines can be used by themselves to give a satisfactory recording layer.
Accordingly, it is the object of this invention to provide additional phthalocyanines which are substituted by metallocene units and to provide improved recording materials based on phthalocyanines for the production of, and for use in, optical recording media. In particular, the metallocenyl-phthalocyanines used as recording materials in optical information recording media, preferably in CD-R, shall fulfill the desired wide-band behaviour (1x-8x) and shall have excellent recording and reproduction characteristics in the wave-length of a semiconductor laser (770-790 nm).
In addition, preferred jitter values in the range of xc2x135 ns and length deviations in the ranges of xc2x140 ns (T3 pits/lands) and xc2x160 ns (T11 pits/lands) shall be maintained.
Furthermore, an improved process for the recovery of the dye used in the production of the recording layer shall be found. It should moreover be possible to use the metallocenyl-phthalocyanines by themselves, i.e. without additional additives, as recording materials.
Accordingly, a metallocenyl-phthalocyanine or its metal complex of a divalent metal, oxometal, halogenometal or hydroxymetal has been found in which at least one of the four phenyl rings of the phthalocyanines contains, bound via a bridge unit E, at least one metallocene radical as substituent, E being composed of a chain of at least two atoms or atom groups selected from the group consisting of xe2x80x94CH2xe2x80x94, xe2x80x94C(xe2x95x90O)xe2x80x94, xe2x80x94CH(C1-C4alkyl)xe2x80x94, xe2x80x94C(C1-C4alkyl)2xe2x80x94, xe2x80x94NHxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94Oxe2x80x94 and xe2x80x94CHxe2x95x90CHxe2x80x94.
In addition there have been found mixtures of the novel compounds which comprise, inter alia, isomers, as well as a process for their preparation, their use and the optical recording media comprising the novel compounds.
A preferred embodiment of this invention relates to metallocenyl-phthalocyanines of formula I 
wherein
M1 is a divalent metal, an oxometal group, halogenometal group or hydroxymetal group, or two hydrogen atoms,
X is halogen, such as chloro, bromo or iodo, preferably chloro or bromo, particularly preferably bromo,
Y1 is xe2x80x94OR1, xe2x80x94OOCxe2x80x94R2, xe2x80x94NHR1, xe2x80x94N(R1)R2, preferably xe2x80x94OR1,
Y2 is xe2x80x94SR1,
R3 is 
R3 is preferably: 
wherein R4 and R5 may be each independently of the other hydrogen or C1-C4alkyl,
n may be a number from 1 to 4,
R6 and R7 are each independently of the other hydrogen, halogen, such as fluoro, chloro, bromo or iodo, C1-C4alkyl, C1-C4alkoxy, amino-C1-C4alkyl, diarylphosphine, or phosphorus-containing C1-C4alkyl, such as xe2x80x94CH2xe2x80x94PAr2 or xe2x80x94CH(Me)xe2x80x94PAr2, Ar being unsubstituted or substituted phenyl,
R8 may be xe2x80x94Oxe2x80x94R9xe2x80x94, xe2x80x94C(xe2x95x90O)xe2x80x94Oxe2x80x94R9 or xe2x80x94Oxe2x80x94C(xe2x95x90O)xe2x80x94R9xe2x80x94, wherein R9 may be a single bond, C1-C4alkylene or C2-C4alkenylene, and M2 is a divalent transition metal, and wherein R12 is hydrogen or methyl, R13 is a single bond, xe2x80x94CH2xe2x80x94, xe2x80x94CH2CH2xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94CH2xe2x80x94C(xe2x95x90O)xe2x80x94 or xe2x80x94CH2CH2xe2x80x94C(xe2x95x90O)xe2x80x94,
x may be a rational number from 0 to 8, preferably from 0 to 5, particularly preferably from 0 to 3,
y1 and y2 may be each independently of the other a rational number from 0 to 6, y1 preferably being an integer from 1 to 6, particularly preferably from 3 to 5, especially preferably from 4, and Y2 preferably being a rational number from 0 to 2.0,
z may be a number from 1 to 4, preferably from 1 to 3, particularly preferably from 1 to 2, and wherein (x+y1+y2+z)isxe2x89xa616,
wherein R1 and R2 may be each independently of the other
C1-C20alkyl which is unsubstituted or substituted by halogen, hydroxy, C1-C20alkoxy, C1-C20alkylamino or C2-C20dialkylamino and which may be interrupted by xe2x80x94O, xe2x80x94Sxe2x80x94, xe2x80x94NHxe2x80x94 or xe2x80x94NR10xe2x80x94, wherein R10 may be C1-C6alkyl,
C5-C20cycloalkyl, C2-C20alkenyl, C5-C12cycloalkenyl, C2-C20alkynyl, C6-C18aryl or C7-C18aralkyl,
and wherein one or two ligands may optionally be bound to the divalent metal atom, the oxometal group, halogenometal group or hydroxymetal group.
The substituents X, Y1, Y2 and R3 are preferably at the benzene nuclei of the metallocenylphthalocyanine I.
The divalent metal used may be divalent transition metal cations, in particular of copper, zinc, nickel, palladium, platinum, manganese or cobalt, preferably of palladium or copper.
The oxometal group used may be VO, MnO or TiO.
The halogenometal group used may be Alxe2x80x94Cl, Alxe2x80x94Br, Alxe2x80x94F, Alxe2x80x94I, Gaxe2x80x94Cl, Gaxe2x80x94F, Gaxe2x80x94I, Gaxe2x80x94Br, Inxe2x80x94Cl, Inxe2x80x94F, Inxe2x80x94I, Inxe2x80x94Br, Tlxe2x80x94Cl, Tlxe2x80x94F, Tlxe2x80x94I, Tlxe2x80x94Br, FeCl, or RuCl and also CrCl2, SiCl2, SiBr2, SiF2, Sil2, ZrCl2, GeCl2, GeBr2, Gel2, GeF2, SnCl2, SnBr2, Snl2, SnF2, TiCl
The hydroxymetal group may be MnOH, Si(OH)2, Ge(OH)2, Zr(OH)2, Mn(OH)2, AlOH or Sn(OH)2.
C1-C20Alkyl is, for example, methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl, n-, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, preferably C1-Cl2alkyl, such as methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl, n-, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and, in particular, branched C3-Cl2alkyl such as i-propyl, sec-, i-, tert-butyl, neopentyl, 1,2-dimethylpropyl, 1,3-dimethylbutyl, 1-isopropyl-propyl, 1,2-dimethylbutyl, 1,4-dimethylpentyl, 2 methyl-1-isopropylpropyl, 1-ethyl-3-methylbutyl, 3-methyl-1-isopropylbutyl, 2-methyl-1-isopropylbutyl, or 1-tert-butyl-2-methylpropyl, and C1-C6alkyl such as methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl, n-, neopentyl, n-hexyl, 2,2-dimethylhexyl, particularly preferably C1-C4alkyl such as methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl and 2,4-dimethyl-3-pentyl. C5-C20Cycloalkyl is, for example, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, cyclopentadecyl, cyclohexadecyl, cycloheptadecyl, cyclooctadecyl, cyclononadecyl, cycloeicosyl, preferably C5-C8cycloalkyl such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl.
C2-C20Alkenyl is, for example, ethenyl, n-, i-propenyl, n-, sec-, i-, tert-butenyl, n-, neopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, eicosenyl, preferably C2-C6alkenyl such as ethenyl, n-, i-propenyl, n-, sec-, i-, tert-butenyl, n-, neopentenyl, n-hexenyl, particularly preferably C2-C4alkenyl such as ethenyl, n-, i-propenyl, n-, sec-, i-, tert-butenyl.
C5-C12Cycloalkenyl is, for example, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclononenyl, cyclodecenyl, cycloundecenyl, cyclododecenyl, preferably C5-C8cycloalkenyl such as cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl.
C2-C20Alkynyl is, for example, ethynyl, n-, i-propynyl, n-, sec-, i-, tert-butynyl, n-, neopentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl, hexadecynyl, heptadecynyl, octadecynyl, nonadecynyl, eicosynyl, preferably C2-C6alkynyl such as ethynyl, n-, i-propynyl, n-, sec-, i-, tert-butynyl, n-, neo-pentynyl, n-hexynyl, particularly preferably C2-C4alkynyl such as ethynyl, n-, i-propynyl, n-, sec-, i-, tert-butynyl.
C6-C18Aryl is, for example, phenyl, 1-, 2-naphthyl, indenyl, azulenyl, acenaphthylenyl, fluorenyl, phenanthrenyl, anthracenyl, triphenylene, preferably phenyl.
C7-C18Aralkyl is, for example, benzyl, phenethyl, phenyl-(CH2)3-12xe2x80x94, preferably benzyl.
C1-C20Alkoxy is, for example, methoxy, ethoxy, n-, i-propoxy, n-, sec-, i-, tert-butoxy, n-, neopentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy, tetradecoxy, pentadecoxy, hexadecoxy, heptadecoxy, octadecoxy, nonadecoxy, eicosoxy, preferably C1-C6alkoxy such as methoxy, ethoxy, n-, i-propoxy, n-, sec-, i-, tert-butoxy, n-, neopentoxy, n-hexoxy, 2,2-dimethylhexoxy, particularly preferably C1-C4alkoxy such as methoxy, ethoxy, n-, i-propoxy, n-, sec-, i-, tert-butoxy.
C1-C20Alkylamino is, for example, methylamino, ethylamino, n-, i-propylamino, n-, sec-, i-, tert-butylamino, n-, neopentylamino, hexylamino, heptylamino, octylamino, nonylamino, decylamino, undecylamino, dodecylamino, tridecylamino, tetradecylamino, pentadecylamino, hexadecylamino, heptadecylamino, octadecylamino, nonadecylamino, eicosylamino, preferably C1-C6alkylamino such as methylamino, ethylamino, n-, i-propylamino, n-, sec-, i-, tert-butylamino, n-, neopentylamino, n-hexylamino, particularly preferably C1-C4alkylamino such as methylamino, ethylamino, n-, i-propylamino, n-, sec-, i-, tert-butylamino.
C2-C20Dialkylamino is, for example, dimethylamino, diethylamino, n-, i-dipropylamino, n-, sec-, i-, tert-dibutylamino, n-, neodipentylamino, dihexylamino, diheptylamino, dioctylamino, dinonylamino, didecylamino, diundecylamino, didodecylamino, ditridecylamino, ditetradecylamino, dipentadecylamino, dihexadecylamino, diheptadecylamino, dioctadecylamino, dinonadecylamino, dieicosylamino, preferably C1-C6alkylamino such as dimethylamino, diethylamino, n-, i-dipropylamino, n-, sec-, i-, tert-dibutylamino, n-, neodipentylamino, n-dihexylamino, particularly preferably C1-C4alkylamino such as dimethylamino, diethylamino, n-, i-dipropylamino, n-, sec-, i-, tert-dibutylamino.
Phosphorus-containing C1-C4alkyl may preferably be diphenylphosphine radical-substituted methylene, ethylene, propylene or butylene such as xe2x80x94CH2xe2x80x94Par2 or xe2x80x94CH(Me)xe2x80x94Par2, Ar being unsubstituted or substituted phenyl.
Diarylphosphine may be, for example, diphenylphosphine and substituted diphenylphosphines.
M2 is, for example, a cation of a transition metal such as titanium, iron, ruthenium, osmium or nickel, preferably iron.
R3 is particularly preferably one of the following radicals: 
wherein R12 may be hydrogen or methyl, and R13 may be a single bond, xe2x80x94CH2xe2x80x94, xe2x80x94CH2CH2xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94CH2xe2x80x94C(xe2x95x90O)xe2x80x94 or xe2x80x94CH2CH2xe2x80x94C(xe2x95x90O)xe2x80x94.
Very particularly preferred radicals R3 are xe2x80x94C(xe2x95x90O)xe2x80x94Oxe2x80x94CH2xe2x80x94Cpxe2x80x94FeCp, xe2x80x94CH2xe2x80x94Oxe2x80x94C(xe2x95x90O)xe2x80x94CH2xe2x80x94CH2xe2x80x94C(xe2x95x90O)xe2x80x94Cpxe2x80x94FeCp, xe2x80x94CH2xe2x80x94Oxe2x80x94C(xe2x95x90O)xe2x80x94Cpxe2x80x94FeCp or xe2x80x94CH2xe2x80x94Oxe2x80x94C(xe2x95x90O)xe2x80x94CH2xe2x80x94Cpxe2x80x94FeCp.
Another preferred embodiment of this invention relates to metallocenyl-phthalocyanines of formula II 
wherein
R11 is C1-C12alkyl, particularly preferably branched C3-C12alkyl, more preferably 2,4-dimethyl-3-pentyl, and M3 is palladium or copper, z is 1 or 2, and R3 is the radicals mentioned above as being particularly or very particularly preferred.
The radicals xe2x80x94OR11 may be in positions 1 to 16; the four radicals xe2x80x94OR11 are preferably in each case in positions 1, 5, 9, 13 or 2, 6, 10, 14, the x halogen radicals, X and the z radicals R3 being in the remaining free positions, preferably in para-position to the xe2x80x94OR11 radicals. Particularly preferably, the four radicals xe2x80x94OR11 are in positions (P1) 1, 5, 9, 13 (xe2x80x9cC4hxe2x80x9d), and X, depending on x, is preferably in the positions selected from the group consisting of 4, 8, 12 and 16, and the z radicals R3 are in para-position to one of the OR11 radicals, i.e. for example in one of the free positions 4, 8, 12 or 16 not occupied by X. X may furthermore also be in positions 2, 3, 6, 7, 10, 11, 14 or 15.
This invention also embraces isomers and isomer mixtures. The xe2x80x94OR11 radicals could, for example, also be in positions (P2) 1, 8, 9, 16 (xe2x80x9cD2hxe2x80x9d) or (P3) 1, 5, 12, 16 (xe2x80x9cC2vxe2x80x9d) or (P4) 1, 5, 9, 16 (xe2x80x9cCsxe2x80x9d). Accordingly, a preferred embodiment of this invention also relates to isomer mixtures containing at least two, particularly preferably three, of the isomeric forms P1, P3 or P4.
The following compounds II serve as illustration: 
Other isomers also result from R3 (always under the condition that it is in para-position to the xe2x80x94OR11 radical at the same benzene nucleus) facing an adjacent OR11 radical (e.g. R3 is in position 5, an xe2x80x94OR11 radical is in position 4) or from R3 not facing any adjacent xe2x80x94OR11 radical (e.g. R3 is in position 5 and there is no xe2x80x94OR11 radical in position 4). Thus, in arrangement P1 (C4h) there are only adjacent positions for R3, whereas in arrangement P2 (D2n) which, probably because of the steric hindrance of the xe2x80x94OR11 radicals, is not found in practice, there are no adjacent positions to take. In arrangements P3 and P4 (C2v and Cs), however, there are two adjacent and two non-adjacent positions for R3. It is self-evident that the arrangement of the halogen atoms X further increases the number of isomers.
A preferred embodiment of this invention relates to the compounds II, which contain one R3 or two R3, and to mixtures which contain one compound II containing one R3 and one compound II containing two R3. A preferred mixture is that which contains 1 to 25 mol %, particularly preferably 5 to 20 mol %, very particularly preferably 5 to 10 mol %, of a compound II containing two R3, and 99 to 75 mol %, particularly preferably 95 to 80 mol %, very particularly preferably 95 to 90 mol %, of a compound II containing one R3, the xe2x80x94OR11, R3, X and M3 groups of the two compounds II being identical.
A very particularly preferred embodiment of this invention relates to metallocenyl-phthalocyanines of formula III 
wherein E may be xe2x80x94CH2Oxe2x80x94(xe2x95x90O)xe2x80x94 or xe2x80x94C(xe2x95x90O)xe2x80x94OCH2xe2x80x94, the formula III presented here showing only one of the possible isomeric compounds (i.e. the arrangement P1 (C4h) of the xe2x80x94OR11 radicals, definition see above). This invention thus also embraces the isomeric compounds having the arrangements P3 or P4 (C2v or Cs), in particular a mixture containing three isomeric compounds having the P1, P3 and P4 arrangements of the xe2x80x94OR11 radicals and compounds in which (zxe2x88x921) is  greater than 0, for example 1, 2 or 3, preferably 1.
A very particularly preferred embodiment of this invention relates to 
where x=2.6 to 3.0, preferably 2.7 to 2.9, more preferably 2.8 and 
where x=0 to 0.5
Another preferred embodiment of this invention relates to mixtures containing at least one of the compounds 11, preferably a mixture consisting of one compound II containing one R3, one compound II containing two R3 and one compound of formula IV 
wherein R14 may be xe2x80x94CHO, xe2x80x94CH2OH, xe2x80x94COOH, xe2x80x94CH2OC(O)xe2x80x94C1-C4alkyl or an acetal such as xe2x80x94CH(Oxe2x80x94C1-C4alkyl)2, and z may be 1 or 2.
A particularly preferred embodiment of this invention relates to a mixture, which comprises
(a) 60 to 95 mol %, preferably 80 to 95 mol %, of a compound II containing one R3 (i.e. z=1),
(b) 5 to 20 mol %, preferably 5 to 10 mol %, of a compound II containing two R3 (i.e. z=2), and
(c) 0 to 25 mol %, preferably 0 to 10 mol %, of a compound IV,
wherein xe2x80x94OR11, R3=R14, X and M3 in formulae II and IV have the same meaning and the mol % amounts make up 100%.
Another preferred embodiment of this invention relates to mixtures, which comprise
(a) 60 to 95 mol %, preferably 80 to 95 mol %, of a compound II, wherein R11 is C1-C12alkyl and M3 is palladium or copper, and z is 1,
(b) 5 to 20 mol %, preferably 5 to 10 mol %, of a compound II containing two R3 (z=2), and
(c) 0 to 25 mol %, preferably 0 to 10 mol %, of a compound IV, wherein R14 may be xe2x80x94CHO, xe2x80x94CH2OH, xe2x80x94COOH, xe2x80x94CH2OC(O)xe2x80x94C1-C4alkyl or an acetal, and z may be 1 or 2,
wherein xe2x80x94OR11, R3=R14, X and M3 in formulae II and IV have the same meaning and the mol % amounts make up 100%.
Another preferred embodiment of this invention relates to mixtures which comprise at least one of the compounds III, preferably a mixture consisting of one compound III containing one radical xe2x80x94Exe2x80x94[CpFeCp] (i.e. z=1), one compound III containing two radicals xe2x80x94Exe2x80x94[CpFeCp] (i.e. z=2) and one compound of formula IV.
Accordingly, a particularly preferred embodiment of this invention also relates to a mixture, which comprises
(a) 60 to 95 mol %, preferably 80 to 95 mol %, of a compound III containing a radical xe2x80x94Exe2x80x94[CpFeCp] (i.e. z=1)
(b) 5 to 20 mol %, preferably 5 to 10 mol %, of a compound III containing two radicals xe2x80x94Exe2x80x94[CpFeCp] (i.e. z=2) and
(c) 1 to 25 mol %, preferably 1 to 10 mol %, of a compound IV,
wherein xe2x80x94OR11 in formula IV is xe2x80x94OCH(CHMe2)2, X is Br, and M3 in formulae III and IV are identical and the mol % amounts make up 100%.
The compounds of this invention are usually obtained by esterifying a phthalocyanine with a metallocene derivative, for example in analogy to the method described in J.Chem.Soc., Chem.Commun. (1995) 1715-1716, the phthalocyanine used being the phthalocyanine of formula V 
wherein R15 may be a hydroxy-, carboxy- or acid chloride-containing radical, preferably xe2x80x94CH2OH, xe2x80x94CH(Me)OH, xe2x80x94COOH, xe2x80x94COCl, and the metallocene derivative used being a compound selected from the group consisting of a hydroxy-, carboxy- and acid chloride-containing metallocene, preferably a metallocenecarbonyl chloride CpM2Cpxe2x80x2xe2x80x94COCl, a metallocenecarboxylic acid CpM2Cpxe2x80x2xe2x80x94COOH and a metallocene alcohol,
the esterification usually being carried out in a manner known per se by reacting the phthalocyanine V (or the metallocene) containing a hydroxy-containing radical with the corresponding metallocene (or phthalocyanine) containing a carboxy- or acid chloride-containing radical, and wherein Cp is 
The other possible R3 radicals which are indicated above are preferably accessible by analogous methods.
If the starting compounds V are xe2x80x94OH-carrying substituents, they are generally accessible by reduction from corresponding formyl compounds, preferably from the corresponding aldehyde, for example by the process described in WO 98/14520. The aldehyde reduction is preferably carried out using a complex metal hydride such as sodium borohydride. The reduction is particularly preferably carried out using a complex metal hydride based on an inert support material such as a zeolite, filter aids, silicates, aluminium oxides (alox), very particularly preferably using sodium borohydride on alox. The carboxyl group can be obtained by oxidation from the corresponding formyt compound in a manner known per se and from that, if desired, the corresponding acid chloride may be obtained.
The formyl compounds in turn are obtained, for example, also by process described in WO 98/14520 by reacting the phthalocyanines VI 
which are known, inter alia, from EP-B 373 643, with phosphoroxy chloride/dimethylformamide or phosphoroxy chloride/N-methylformanilide.
The corresponding halogenated compounds I to V (xxe2x89xa00) are obtained, for example, by halogenating the corresponding formyl compounds before reducing them to the corresponding alcohol compounds V.
The halogenation can be carried out by customary methods, such as those described in EP-A 513,370 or EP-A 519,419, for example by charging, if desired with heating, the correspondingly substituted phthalocyanines V or VI with bromine in an organic solvent such as saturated hydrocarbons, ethers or halogenated hydrocarbons orxe2x80x94as in the method described in EP-A 703,281xe2x80x94in a two-phase system consisting of water and a halogenated aromatic solvent which is essentially immiscible with water.
The metallocenecarbonyl compounds used may preferably be carbonyl chlorides such as ferrocenecarbonyl chloride and 
preferably ferrocenecarbonyl chloride, 
Metallocenecarbonyl compounds are normally commercially available or are accessible in accordance with known instructions, such as those given in Org. Synthesis 56 (1977) 28-31.
The molar ratio of metallocenecarbonyl compound to compound V depends on the desired degree of esterification. It is preferred to choose a range from 5:1 to 0.5:1, particularly preferably from 2:1 to 1:1.
The reaction is usually carried out using a solvent. Solvents used are, for example, aprotic organic solvents such as pyridine, chlorobenzene, toluene, tetrahydrofuran, chloroform, methylene chloride or ethyl acetate, or mixtures thereof.
It is preferred to use basic solvents, especially if the esterification is carried out using acid chloride such as pyridine or tertiary amines, for example those which are cited in xe2x80x9cTechniques of Chemistryxe2x80x9d, Vol. II, organic solvents, phys. properties and methods of purification, J. A. Riddick, W. B. Bunger, Th. K. Sakano, J. Wiley-Interscience Publication, 1986, in which case it is preferred to add a non-nucleophilic base, such as pyridine, or tertiary alkylamines, such as triethylamine. The ratio of base to acid chloride is usually chosen to be in the range from 1:1 to 10:1.
The ratio of solvent to compound V is usually chosen to be in the range from 2:1 to 30:1, preferably from 5:1 to 20:1.
The reaction temperature is usually chosen to be in the range from 0xc2x0 C. to the reflux temperature under ambient pressure, preferably from room temperature to 100xc2x0 C.
According to findings to date, the reaction pressure is not critical for the success of the invention. It is usefully chosen to be in the range from 70 kPa to 5 MPa, preferably from 90 to 120 kPa.
The reaction is preferably carried out under inert gas, such as nitrogen, or under a noble gas, such as neon or argon.
The compounds of this invention are also accessible by reducing the formyl compounds obtainable from the phthalocyanines VI by the method described in WO 98/14520 to the corresponding alcohol compounds, for example using sodium borohydride, and then esterifying them with a metallocenyl radical with subsequent halogenation.
It is also possible to first halogenise the formyl compounds, then to oxidise the formyl radicals to the carboxylic acid, subsequently to prepare the acid chloride therefrom and then to carry out esterification using a metallocenyl radical.
Finally, the formyl compounds can be oxidised to the corresponding carboxylic acid-containing phthalocyanines, the carboxylic acid unit can be reacted to the carboxylic acid chloride unit and can then be esterified with a metallocenyl radical and halogenised.
This invention also relates to an optical recording medium, which comprises a substrate, a recording layer, a reflecting or partly reflecting layer and, if desired, a protective layer, the recording layer containing a phthalocyanine of this invention.
If desired, the inventive optical recording medium can also contain more than one recording layer and/or more than one reflecting or partly reflecting (semitransparent) layer.
The substrate functioning as support for the layers applied to it is usually semitransparent (i.e. has a transparency T of at least 10%) or, preferably, transparent (Txe2x89xa790%). The support may be 0.01 to 10 mm thick, preferably 0.1 to 5 mm thick.
The recording layer is preferably arranged between the transparent substrate and the reflecting layer. The recording layer is usually from 10 to 1000 nm thick, preferably from 50 to 500 nm thick, particularly preferably around 100 nm thick, for example from 80 to 150 nm thick. The absorption of the recording layer is usually from 0.1 to 2.0, preferably from 0.5 to 2.0, at the absorption maximum. With very particular preference, the layer thickness is chosen in a known manner, dependent on the respective refractive indices in the unwritten or written state at the readout wave-length, such that there is constructive interference in the unwritten state and destructive interference results in the written state, or vice versa.
The reflecting layer, which may usually be from 10 to 150 nm thick, preferably has high reflectivity (Rxe2x89xa770%) coupled with low transparency (Txe2x89xa610%).
The layer which is topmost depending on the layer structure, for example the reflection layer or the recording layer, is preferably additionally provided with a protective layer, which usually can have a thickness in the range from 0.1 to 1000 xcexcm, preferably from 0.1 to 50 xcexcm and, particularly preferably, from 0.5 to 15 xcexcm. This protective layer may, if desired, also serve as an adhesion promoter for a second substrate layer applied thereon, which is preferably from 0.1 to 5 mm thick and consists of the same material as the support substrate.
The reflectivity of the entire recording medium is preferably at least 60%, particularly preferably at least 65% at the writing wave-length of the laser used.
Examples of suitable substrates are glasses, minerals, ceramics and thermosets or thermoplastics. Preferred supports are glasses and homo- or copolymeric plastics. Examples of suitable plastics are thermoplastic polycarbonates, polyamides, polyesters, polyacrylates and polymethacrylates, polyurethanes, polyolefins, polyvinyl chloride, polyvinylidene fluoride, po lyimides, duroplastic polyesters and epoxy resins. The substrate can be in pure form or can also contain customary additives, for example UV absorbers or dyes, as is proposed, inter alia, in JP 04/167 239, as light protection for the recording layer. In the latter case it may be convenient for the dye added to the support substrate to have an absorption maximum which is hypsochromically shifted by at least 10 nm, preferably by at least 20 nm, relative to the dye of the recording layer.
The substrate is preferably transparent in at least part of the range from 600 to 830 nm, so that it is permeable to at least 90% of the incident light of the writing or readout wave-length. On the side of the coating, the substrate preferably has a spiral guide groove with a groove depth from usually 50 to 500 nm, a groove width from usually 0.2 to 0.8 xcexcm and a radial distance between 2 adjacent turns from usually 0.4 to 1.6 xcexcm, particularly preferably having a groove depth from 100 to 300 nm and a groove width from 0.3 to 0.6 xcexcm.
Instead of the substrate, the recording layer itself can have a guide groove, as is described, inter alia, in EP-A 392 531.
The recording layer preferably consists exclusively or essentially of one or more phthalocyanines of this invention. To increase the stability still further, however, it is also possible if desired to add known stabilisers in customary amounts, for example a nickel dithiolate described in JP 04/025 493 as light stabiliser. Additional dyes may optionally be added, although the amount of such dyes is conveniently not more than 50% by weight, preferably not more than 10% by weight, based on the recording layer. Since the advantages of the novel recording media are based on the novel phthalocyanines, it is useful for the optionally added dye to have a hypsochromically shifted absorption maximum relative to the novel phthalocyanine, and for the amount of the added dye to be kept so small that the proportion of the latter in the overall absorption of the recording layer in the region from 600 to 830 nm is not more than 20%, preferably not more than 10%. With particular preference, however, no additional dye is added.
A particularly suitable reflective material for the reflection layer comprises metals which are good reflectors of the laser radiation used for recording and reproduction, examples being the metals of the third, fourth and fifth main groups and subgroups of the Periodic Table of the chemical elements. Particularly suitable metals are Al, In, Sn, Pb, Sb, Bi, Cu, Ag, Au, Zn, Cd, Hg, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt and the lanthanide metals Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and also their mixtures and alloys. For reasons of high reflectivity and ease of preparation, particular preference is given to a reflection layer of aluminium, silver, copper, gold or their alloys.
Suitable materials for the protective layer are predominantly plastics, which can be applied in a thin layer either directly or with the aid of adhesion layers to the support or the topmost layer. It is judicious to choose mechanically and thermally stable plastics having good surface properties, which can be additionally modified, for example written on. The plastics can either be thermosets or thermoplastics. Preference is given to radiation-cured (for example by means of UV radiation) protective layers, which are particularly easy and economic to prepare. Large numbers of radiation-curable materials are known. Examples of radiationcurable monomers and oligomers are acrylates and methacrylates of diols, triols and tetrols, polyimides of aromatic tetracarboxylic acids and aromatic diamines having C1-C4alkyl groups in at least two positions ortho to the amino groups, and oligomers containing dialkyl groups, for example dimethylmaleinimidyl groups.
The novel recording media can also feature additional layers, for example interference layers. It is also possible to construct recording media having a plurality of (for example two) recording layers. The construction and use of such materials are known to the skilled person. If such layers are present, preference is given to interference layers which are disposed between the recording layer and the reflecting layer and/or between the recording layer and the substrate and which consist of a dielectric material, for example as described in EP-A 353 393, consisting of TiO2, Si3N4, ZnS or silicone resins.
The novel recording media can be prepared by processes known per se, it being possible to employ various coating methods depending on the materials used and on their functioning.
Examples of suitable coating methods are dipping, flow coating, spreading, knife coating and spin-coating, and also high-vacuum vapour deposition methods. When using flow coating methods, for example, solutions in organic solvents are generally used. When using solvents, care should be taken to ensure that the supports used are insensitive to these solvents. It is a particular advantage of the novel dyes that, even as pure compounds or as mixture of only few components, they are readily soluble in less polar solvents, making it possible to forego the use both of aggressive solvents such as acetone and of complicated isomeric mixtures. Suitable coating methods and solvents are described, inter alia, in EP-A 401 791.
The recording layer is preferably applied by spin-coating a dye solution, solvents that have been found appropriate being, in particular, alcohols such as 2-methoxyethanol, cyclopentanol, isopropanol, isobutanol, diacetone alcohol or n-butanol, preferably cyclopentanol, diacetone alcohol, or preferably, fluorinated alcohols such as 2,2,2-trifluorethanol or 2,2,3,3-tetrafluoro-1-propanol and also cyclohexane, methylcyclohexane and diisobutyl ketone, or mixtures thereof.
The metallic reflection layer is preferably applied by sputtering or vapour deposition under vacuum. The sputtering technique is particularly preferred on account of the high degree of adhesion to the support for the application of the metallic reflection layer. This technique is described in detail in textbooks (e.g. J. L. Vossen and W. Kern, xe2x80x9cThin Film Processesxe2x80x9d, Academic Press, 1978) as well as in the state of the art (e.g. EP-A 712 904), no further details thus needing to be provided here.
The structure of the novel recording medium depends principally on the readout methods; known functional principles are the measurement of the change in transmission or, preferably, in reflection.
If the recording material is constructed in accordance with the change in reflection, then the following structures are examples of those which can be employed: transparent support/recording layer (one or more layers)/reflection layer and, if useful, protective layer (not necessarily transparent), or support (not necessarily transparent)/reflection layer/recording layer and, if useful, transparent protective layer. In the former case the light is irradiated from the support side, while in the latter case the radiation is incident from the side of the recording layer or, if appropriate, from the side of the protective layer. In both cases the light detector is on the same side as the light source. The former construction of the recording material to be used in accordance with the invention is generally preferred.
If the recording material is constructed in accordance with the change in light transmission, the following alternative structure is a suitable example: transparent support/recording layer (one or more layers) and, if useful, transparent protective layer. The light for recording and for readout can be irradiated alternatively from the support side or from the side of the recording layer or, if appropriate, form the side of the protective layer, the light detector in this case always being on the opposite side.
Another embodiment of this invention therefore relates to an optical recording medium which comprises a novel metallocenyl-phthalocyanine or mixtures thereof or a metallocenyl-phtha2-locyanine prepared according to this invention.
A preferred embodiment of this invention relates to an optical recording medium, which consists of a transparent substrate, a recording layer on this substrate, a reflection layer on the recording layer and, if desired, a final protective layer, the recording layer comprising a metallocenyl-phthalocyanine, or mixtures thereof, which is novel or which is prepared according to this invention.
Recording (inscribing, writing) and reading out the information is preferably carried out using laser radiation. Examples of suitable lasers are commercial available semiconductor diode lasers, typically GaAsAl, InGaAlP, GaAs or GaN laser diodes with a wave-length of 635, 650, 670, 680, 780 or 830 nm, or 390-430 nm, or gas/ion lasers, for example He/Ne, Kr, HeCd or Ar laser with a wave-length of 602, 612, 633, 647, or 442 and 457 nm.
Recording is preferably effected by inscribing pits of variable length using laser radiation which is pulse duration-modulated and focussed on the recording layer. The recording speed is chosen depending on the focus geometry and the laser performance and may be, for example, in the range from 0.01 to 100 m/s, preferably from 1-10 m/s.
The readout of the information is preferably carried out by spatially resolved measurement of the reflection or transmission using laser radiation of low capacity and a photodetector, it being particularly advantageous that laser radiation of the wave-length used for recording may be employed, so that no second laser apparatus need be used. Accordingly, in a preferred embodiment of the invention the information is recorded and read out at the same wave-length. During readout, the capacity of the laser is usually reduced over the laser radiation used for recording, e.g. from ten to fifty times. In the recording material used according to this invention, the information can be readout once or several times. Suitable photodetectors preferably include PIN and AV photodiodes as well as CCD (charge-coupled devices). The novel phthalocyanines make it possible to record information with a high degree of reliability and durability and these recordings are distinguished by having excellent mechanical and thermal stability, high stability to light and sharp edge zones of the optical pits. Particular advantages are the high signal/noise ratio as well as the high optical resolution which permits flawless recording and readout of the signals even at high speed (xe2x89xa74x) and at the same time with small jitter.
The novel medium is, in particular, an optical information medium of the WORM type. It can be used, for example, as a playable CD (compact disc), as recording material for computer and video appliances, as an identity and security card, or for the production of diffractive optical elements such as holograms.
This invention therefore also relates to the use of the novel recording medium for the optical recording, storage and reproduction of information, for the production of diffractive optical elements or for the recording of holograms. Recording and reproduction preferably take place in the wave-length range from 400 to 500 nm or, particularly preferably, from 600 to 830 nm.
Owing to the use of the novel dyes, the novel recording media have advantageously homogeneous, amorphous and low-scatter recording layers, the absorption edges of which are steep in the solid phase. Other advantages are the high light stability in daylight and under low laser radiation coupled with high sensitivity under high laser radiation, the uniform writing width, the good stability to heat and storage and, in particular, the high optical resolution and very small jitter.